Traffic engineering is a key issue in designing and operating a network with traffic demand that changes over time due to network traffic growth or traffic pattern changes. One approach to address the above problems is to use the shortest path method, where the length of a link is its static latency as defined by the length of the underlying optical fiber route. However, this approach only takes into account of the static delay introduced by non-packet based network equipment, such as optical switches and cross-connect. Therefore, this approach cannot address the above problems with accuracy, especially in a packet based network environment where total latency varies with network loading, for latency sensitive network services such as VoIP services.